#Solar mooc 2009 nabcep study guide solutions 1-29

April 2009 NABCEP Study
Guide Questions 1-29
SolPowerPeople, Inc.
Austin, TX

March 8, 2012

Problem 1

  1. b. “as required by OSHA Subpart E.”

  Seems to be an error in this answer. NABCEP indicates subpart
“E”. OSHA indicates subpart “M”.
  1926.501(b)(1)
  "Unprotected sides and edges." Each employee on a walking/working surface (horizontal and vertical surface)
with an unprotected side or edge which is 6 feet (1.8 m) or more above a lower level shall be protected from falling
by the use of guardrail systems, safety net systems, or personal fall arrest systems.

Problem 2

  2. b. reference OSHA Subpart E.

Problem 3

  3. A. “See section 3.1.2” (of NABCEP Study Guide)

  “The severity of the shock depends on the path of current
flow through the body, the amount of current, and the
duration of the exposure”

Problem 4

  4. A. “See section 3.1.2” (of NABCEP Study Guide)

  “Currents above 10 mA can paralyze or “freeze” muscles.”

Problem 5

  5. D. “See section 3.1.2” (of NABCEP Study Guide)

  “Currents of more than 75 mA ac can cause a rapid,
ineffective heartbeat, and can result in death in minutes
unless a defibrillator is used.”

Problem 6

  6. A. “See section 3.1.2”

  “Lockout and tagging is used to prevent unknowing
individuals from energizing electrical circuits while they are
being serviced or maintained.”

Problem 7

  7. B. “See section 3.1.3” (of NABCEP Study Guide)

  “Consequently, OSHA requires that fall protection be used
for walkways and ramps, holes and excavations, roofs, and
wall openings where an employee or worker can fall 6 feet
or more.”

Problem 8


  “Guardrails used to protect open-sided floors and platforms
must have top rails between 39 and 45 inches tall, a mid rail,
and toeboards at least 3-1/2 inches high.”

Problem 9

  9. B. “See section 3.1.3”

  “Guardrails used to protect open-sided floors and platforms
must have top rails between 39 and 45 inches tall, a mid rail,
and toeboards at least 3-1/2 inches high.”

Problem 10

  10. D. “See section 3.1.3”

  “Safety nets must be deployed no further than 30 feet below
where work is performed, preferably closer.”

Problem 11

  11. C. “See section 3.1.4”

  “OSHA requires that a stairway or ladder be used at points
of access where there is an elevation break of 19 inches or
more on a jobsite.”

Problem 12

  12. A. “See section 3.1.4”

  “Stairways with four or more risers, or higher than 30
inches, must be equipped with at least one handrail, capable
of withstanding a force of 200 pounds.”

Problem 13

  13. B. “See section 3.1.4”

  “Stairways with four or more risers, or higher than 30
inches, must be equipped with at least one handrail, capable
of withstanding a force of 200 pounds.”

Problem 14

  14. D. “See section 3.1.4”

  “Stairs must be installed between 30 and 50 degrees, must
have uniform riser height and tread depth, with less than a
1/4-inch variation.”

Problem 15

  15. B. “See section 3.1.4”

  “Stairways landings must be at least 30 inches deep and 22
inches wide at every 12 feet or less of vertical rise.”

Problem 16

  16. B. “See section 3.1.4”

  “Non-self-supporting ladders (those that lean against a
wall or other support) must be positioned at an angle
where the horizontal distance from the top support to
the foot of the ladder is 1/4 the working length of the
ladder.”

  The working height is 20 feet. 1/4th of 20 is 5 feet.

Problem 17

L = (12)2 + (3)2 + 3
L = 144 + 9 + 3
L = 153 + 3
L = 12.4 + 3
L = 15.4 feet

Problem 17
3.1.4 “When using a portable ladder for access to an
upper landing surface, the side rails must extend at least 3 feet as
3 feet above the upper landing surface.” required by
OSHA

2 2
L = (12) + (3) + 3
Unknown
L = 144 + 9 + 3 length 12 feet

L = 153 + 3
L = 12.4 + 3
3 feet (i.e. ¼ of 12 as required by
L = 15.4 feet OSHA)

Problem 18

  18. D. “See section 3.1.4” If using ladders where the
employee or the ladder could contact exposed energized
electrical equipment, such as transformers or overhead
services, ladders must have nonconductive side rails such as
wood or fiberglass.

Problem 19

  19. D. “See section 3.1.6”

  “Class B hardhats are intended for electrical and utility
work, and protect against falling objects, as well as high-
voltage shock and burns.” from NABCEP Study Guide.

Problem 19

  WRONG!: Hard hats are classified based on ANSI
Z89.1. The 1986 revision had a Class B classification for
high voltage. This classification changed in 1997 to
Classes G & E.

Problem 20


  “Employee responsibilities include using PPE in accordance
with training received and other instructions, and inspecting
daily and maintaining in a clean and reliable condition.”

Problem 21

  21. D. “See section 3.1.6”

  “Eye protection must be provided to protect against hazards such as dust and
other flying particles, corrosive gases, vapors, and liquids, and welding operations.”

Problem 22

Note: NABCEP loves this question!

Problem 22

  22. C.

  C is the best answer because (a) is not at the level of the
workers, (b) may be distracted, and d is not at the level of
the workers and not in communication with them while
they work.

Problem 22
"Safety monitoring systems." Safety monitoring systems [See 1926.501(b)(10) and 1926.502(k)] and their use
shall comply with the following provisions:

1926.502(h)(1)
The employer shall designate a competent person to monitor the safety of other employees and the employer
shall ensure that the safety monitor complies with the following requirements:
1926.502(h)(1)(i)
The safety monitor shall be competent to recognize fall hazards;
..1926.502(h)(1)(ii)
1926.502(h)(1)(ii)

The safety monitor shall warn the employee when it appears that the employee is unaware of a fall hazard or is
acting in an unsafe manner;

1926.502(h)(1)(iii)
The safety monitor shall be on the same walking/working surface and within visual sighting distance of the
employee being monitored;
1926.502(h)(1)(iv)
The safety monitor shall be close enough to communicate orally with the employee; and
1926.502(h)(1)(v)
The safety monitor shall not have other responsibilities which could take the monitor's attention from the
monitoring function.

Problem 23

  23. B. The module and wiring can withstand short-circuit
current of the module, even if modules are connected in
series or parallel. (Wiring must be sized accordingly.)

Problem 23
  Consider this. Modules have a nameplate rating for Isc
(short-circuit current) under STC (standard test conditions)
which is an irradiance of 1,000 watts per square meter

Problem 23

  Now consider that all
modules have a “series
fuse rating” which is an
indication of the
ampacity of the device,
as in how much current
the device can handle.

Problem 23
  This implies that in
order for the module
2
Isc@1, 000watts / m = 6.25 to produce current
greater than the
20amps / 6.25amps = 3.2 ampacity of the
module itself, it would
3.2 ×1, 000W / m 2 = 3, 200W / m 2 been to be exposed to
an irradiance level of
3,200 watts per square
meter which you
would never see with
terrestrial irradiation.

Problem 24

  24. C. Multiply the open-circuit voltage by 1.18. B

  Be sure to use the −20°C correction factor from NEC Table
690.7.

Problem 25

  25. B. The GFP is designed to provide fire protection. The
GFCI protects people from shock.

Problem 25

 From 3.5.4.1: The 2008 NEC, in article
690.5 requires that all grounded PV
arrays must incorporate a ground-fault
protection device to reduce fire hazards.

Problem 26

  26. C. The module maximum power voltage decreases at the
rate of -0.5%/°C (rule of thumb) for module temperatures
above 25°C.

  Hence, at 60°C, the module voltage will have decreased by
0.5×(60−25) = 17.5%, resulting in Vmp = 14.1 V.

Problem 27

  27. A. See NEC 480.9(A). Note that option (c) represents an
implementation of (a), but is not exact NEC wording.

Problem 28

  28. C. “See instructions from equipment and battery
manufacturers.”
  “When vented lead-acid batteries are used, they should not be located
beneath any electronic components. The corrosive vapors from the batteries
can degrade the circuitry in the electronic equipment causing premature
failures.”
  The answer implies all of the other battery types listed produced outgassing
that can damage electronic equipment.

Problem 29

  29. B. See any instructions from manufacturers of storage
batteries or equipment that uses storage batteries.

  From section 3.1.9: “If batteries are used outdoors in cold
climates, the electrolyte freezing temperature increases as the
batteries discharge. If the electrolyte freezes, DO NOT CHARGE
THE BATTERY. Let it thaw slowly in a place where, if it should
rupture, the electrolyte will be contained. Do not attempt to
accelerate the thawing process with anything that might be
capable of igniting any gases that may be liberated.”

#Solar mooc 2009 nabcep study guide solutions 1-29

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